#include<iostream>
#include<algorithm>
#include<math.h>
#include<iomanip>
using namespace std;
int main(){
    int a,b;
    while (cin>>a>>b&&a<10000&&b<10000)
    {
        double n=a,sum=0;
        for (int i = 0; i < b; i++)
        {
            
            sum+=n;
            n=sqrt(n);
        }
        cout<<fixed<<setprecision(2)<<sum<<endl;
        
    }
    
}